In order to monitor communication quality of packet communication, a number of discarded data packets is collected in a packet apparatus. For example, a packet may be provided with a discard counter in each buffer in which packets may be discarded, and a processor provided in the packet apparatus may use software processing to sequentially inquire each discard counter and collects number of discarded packets counted in each discard counter.
Related art is disclosed in Japanese National Publication of International Patent Applications No. 2005-51736, 2005-210756, 2010-213239, 2004-320458 and 8-214002.